From time to time all types of cattle require immobilization for various types of treatment, including drugs, vitamins, branding, ear tagging, along with general examination. To accomplish this, the animals are herded into a narrow chute designed to confine the animal during the necessary treatments. Typically squeeze chutes of this nature involve a pair of doors or gates which form the head gate and swing inward to block the path of the animal in its shoulder area, allowing the head to pass therethrough. Typically the chutes include a pair movable sidewalls which prevent the animal from turning around once in the chute. Also included is an entrance gate at the rear of the squeeze chute which blocks the animal from backing out of the chute. Once the animal is stopped within the chute, the sidewalls are usually brought closer together to further prevent movement of the animal. The head gates, typically in the closed position, surround the neck of the animal and restrict vertical movement of the head as well as the side to side movement.
Most head gates on the market today rotate about a horizontal axis located at the ground level or below with lateral movement of the gates in unison to the closed position. Gates of this nature are typified in applicant's own U.S. Pat. No. 5,263,438 and the patent to Simington, U.S. Pat. No. 4,702,200. Typically head gates and squeeze chutes are constructed from heavy gauge steel tubing and are rigid. They provide no flexing when the animal slams into the closing gates. This abrupt deceleration of a heavy animal causes a degree of trauma to the animal and is the primary problem the present invention is attempting to avoid.
A partial solution to this problem is addressed in applicant's above-mentioned patent wherein the head gate itself is spring mounted to the squeeze chute frame so there is a degree of give as the animal impacts the head gate.
A second type of head gate wherein the pair of gates rotate about a vertical axis positioned along the sides of the chute are typified in the U.S. Pat. No. 4,201,157 to Lambert wherein a pair of gates swing like conventional doors and as the gates come in contact with the animal they are moving in the opposite direction of the animal towards there fully closed position. The closing impact velocity which the animal experiences along with the trauma is thereby increased due to the direction of movement of the closing gates.
A variation of the last mentioned patent is shown in the U.S. Pat. No. 5,331,923 to Mollhagen, wherein the vertical axis of the gates is offset and to the rear of the gates.
This same problem is addressed in the patent to Akins, U.S. Pat. No. 5,111,773. In this patent, the axis of movement of the door is conventionally located in the plane of the gate. However, in the opened position, the gates are folded inward in the squeeze chute and swing outward toward their closed position as they engage the animal which also provides a slower closing velocity. From a design standpoint, folding the gates inward creates limitations as to moving the sidewalls of the chute inward to restrict the animal.